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Method for refining cyclohexanone oxime gaseous-phase rearrangement products

A technology of cyclohexanone oxime and gas phase, which is applied in the field of refined cyclohexanone oxime gas phase rearrangement products, which can solve the problems of additional recovery devices and the inability to meet the national high-grade product index of caprolactam products, and achieve the effect of saving investment and operating costs

Inactive Publication Date: 2019-04-05
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to improve the total yield of the gas-phase rearrangement process, this part of caprolactam must be recovered, so additional recovery equipment and energy consumption are required; moreover, the recovered caprolactam cannot reach the national high-grade product index of caprolactam products

Method used

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  • Method for refining cyclohexanone oxime gaseous-phase rearrangement products

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0081] Provide the gas phase rearrangement product of cyclohexanone oxime to be refined, add diisopropyl ether and methanol with 6% mass of diisopropyl ether to the gas phase rearrangement product of cyclohexanone oxime, the mass ratio of rearrangement product to total solvent The ratio is 1.5:1, fully dissolved at 67°C, then crystallized at 15°C, and preliminarily refined caprolactam is obtained after centrifugation. The crude hexane is desolventized under the operating conditions of the negative pressure of the desolventization tower being -80kpa, the temperature of the tower bottom is 100°C, and the temperature of the top of the tower is 70°C; the caprolactam after desolvation is in the distillation tower Distillation is carried out under the operating condition of temperature control at 130° C. to obtain the final product, and the recovery rate of caprolactam is 99%. The recovered caprolactam has a purity greater than 99.99%.

Embodiment 2

[0083] Provide the gas phase rearrangement product of cyclohexanone oxime to be refined, add diisopropyl ether and methanol with 6% mass of diisopropyl ether to the gas phase rearrangement product of cyclohexanone oxime, the mass ratio of rearrangement product to total solvent The ratio is 1:1.5, fully dissolved at 67°C, then crystallized at 15°C, and preliminarily refined caprolactam is obtained after centrifugation. The crude hexane is desolventized under the operating conditions of the negative pressure of the desolventization tower being -80kpa, the temperature of the tower bottom is 100°C, and the temperature of the top of the tower is 70°C; the caprolactam after desolvation is in the distillation tower Distillation was carried out under the operating condition of temperature control at 130° C. to obtain the final product, and the recovery rate of caprolactam was 83%. The recovered caprolactam has a purity greater than 99.99%. Compared with Example 1, increasing the rati...

Embodiment 3

[0093] Provide the gas phase rearrangement product of cyclohexanone oxime to be refined, add diisopropyl ether and methanol with a mass of 0.5% of diisopropyl ether to the gas phase rearrangement product of cyclohexanone oxime, the mass ratio of the rearrangement product to the total solvent The ratio is 1.5:1, fully dissolved at 67°C, then crystallized at 15°C, and preliminarily refined caprolactam is obtained after centrifugation. The crude hexane is desolventized under the operating conditions of the negative pressure of the desolventization tower being -80kpa, the temperature of the tower bottom is 100°C, and the temperature of the top of the tower is 70°C; the caprolactam after desolvation is in the distillation tower Distillation is carried out under the operating condition of temperature control at 130° C. to obtain the final product, and the recovery rate of caprolactam is 99%. The recovered caprolactam has a purity of 99.91%. Compared with Comparative Example 2, addi...

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Abstract

The invention provides a method for refining cyclohexanone oxime gaseous-phase rearrangement products. The method is characterized by comprising steps of dissolving the to-be-refined cyclohexanone oxime gaseous-phase rearrangement products in crystalline solvents and then carrying out crystallization and solid-liquid separation to obtain crude caprolactam; carrying out desolvation and distillationon the crude caprolactam to obtain refined caprolactam. The crystalline solvents include main solvents and a co-solvent; the main solvents are at least one type of ether, hydrocarbon and halohydrocarbon; the co-solvent is alcohol. The method for refining the cyclohexanone oxime gaseous-phase rearrangement products has the advantages that the method is particularly applicable to carrying out desolvation, dehydration and light impurity removal on rearrangement reaction liquid and is particularly applicable to the cyclohexanone oxime gaseous-phase rearrangement products which are yet to be subjected to heavy component removal treatment; the method includes simple technological processes, is high in product yield and few in residue and is environmentally friendly.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a method for refining cyclohexanone oxime vapor phase rearrangement products. Background technique [0002] Caprolactam is produced industrially by subjecting cyclohexanone oxime to a liquid-phase Beckmann rearrangement reaction under oleum-catalyzed conditions to generate caprolactam. At present, a relatively new process is that cyclohexanone oxime undergoes Beckmann rearrangement in the gas phase under the catalysis of a solid acid catalyst to generate caprolactam. Gas-phase rearrangement products contain caprolactam, water and various impurities, and most of them are dehydrated, delightened, and deweighted to obtain initially refined caprolactam. In the third step of fractionation deweighting, the tower bottom liquid is called cyclohexanone oxime vapor phase rearrangement product fractionation heavy raffinate, which contains caprolactam and impurities with a higher boiling point...

Claims

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Application Information

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IPC IPC(8): C07D223/10
CPCC07D223/10
Inventor 徐风华管健粟昀江群航谯荣旷志刚
Owner CHINA PETROLEUM & CHEM CORP
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